Traditionally, the accurate description of the anatomic alterations and physiological sequellae of congenital cardiac malformations has depended upon cardiac catheteriztion and selective angiocardiography. It must be recognized that these techniques are associated with substantial risk in the neonatal period and lesser, although still significant risk, in small children. Thus, the development of accurate, non-invasive methods to assist in the diagnosis and management of heart disease is of particular importance in the pediatric age group. The specific aim of this proposal is to develop and refine three non-invasive modalities whose combined applications may be expected to significantly improve the clinical aproach to the infant or child with heart disease. The techniques to be employed include scintillation scanning of the heart and lungs, phased multiple crystal echocardiography, and pulsed Doppler echocardiography. Scintillation scanning will be employed primarily to assess the magnitude of intercirculatory shunting. The goal of the ultrasonic instrument development program will be to assemble an ultrasonic echographic system utilizing, in combination, the technologies of multi- scan echocardiography, pulse Doppler velocity indication, phased array beam steering, and moving target indicator techniques, in order to provide a high resolution image of internal soft tissue structures. Individually, each of these ultrasound approaches has been demonstrated to have advantage over traditional, single element, mechanically scanned pulse echo techniques for cardiac visualization. It is our conviction that these new approaches used in combination, and exploiting the unique advantages of each, will provide a significantly improved image of cardiac and vascular structures and thus, enhance the capability for atraumatic description of cardiovascular morphology and function in infants and children. It should be recognized that infants and children are especially well suited for ultrasound examinations since considerations of patient size, bone density, and acoustical attenuation all serve to enhance diagnostic accuracy.